Harken Backstay Adjuster

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Dan Corcoran
Posts: 305
Joined: Sun Jan 29, 2017 4:32 pm

Harken Backstay Adjuster

Post by Dan Corcoran »

I posted in the rules question at this link asking about experience with the Harken backstay adjuster. Anyone have experience?
viewtopic.php?f=7&p=1340#p1340

I have installed it temporarily just using a line from the bottom to the stern, and find it's difficult to operate. I am facing decisions like
* How much to shorten the backstay / what is the best height to install adjuster to minimize interference with the lifelines. Clearly it needs to be shorten somewhat or it interferes with the removable storage box.
* As this adjuster pumps in both directions, not just one, it's not clear that the best position is to install is straight back into the cockpit, as opposed to either side.
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Vento Solare
Posts: 418
Joined: Wed Dec 31, 1969 8:00 pm
Location: Newport, RI

Re: Harken Backstay Adjuster

Post by Vento Solare »

Dan - I don't have one but if I were fitting it, I would do the following.
  • Put on the stern locker
  • close the stern lifelines
  • position the adjuster handle just above the dockbox so it does not interfere when the handle is down. Move up as needed to clear the lifeline. I think the lifeline needs to be inside the handle or it will interfere with the handle throw.
  • Determine if a toggle is needed on the bottom to position the adjuster at the location you determined as optimal.
  • Put in the toggle on the bottom and the Harken adjuster - I think the handle needs to face the bow, so make sure the toggle supports that
  • Mark your backstay with the adjuster extended - then have the rigger install a swage fitting to attach at the top of the adjuster
Dan Corcoran
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Re: Harken Backstay Adjuster

Post by Dan Corcoran »

Thanks Bill!
Bengt J
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Re: Harken Backstay Adjuster

Post by Bengt J »

Dan, I think the best way is to mount the Harken on the SS rod connecting the backstay to the stern (this is a standard part of the backstay assembly and must be used regardless of adjuster installed). At that location it will clear the stern box. Extend the Harken assembly fully and pull the backstay hand tight and mark it at the centre of the clevis pin, then ask your sailmaker how much additional slack is needed in light air, that should be the length of the fixed portion of the backstay.
If you need to change the rotation of the Harken add a toggle between the rod and the adjuster, adjust the cut length of the backstay accordingly.
Dan Corcoran
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Re: Harken Backstay Adjuster

Post by Dan Corcoran »

I am getting to like this backstay adjuster, forget my earlier complaint.

It has loosened up after some use becoming easier to pump in both directions.

Riggers are still to busy to put in that rod for me, that is the next step, which should raise it up and make it more accessible.
Dan Corcoran
Posts: 305
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Re: Harken Backstay Adjuster

Post by Dan Corcoran »

Since the original rod from the stern to the backstay is required equipment, the installation and positioning really have no options except maybe to have the handle pull back into the cockpit (default) or to the side (extra hardware)

The installation does require the backstay shortened. After doing so (replacing the temporary lashing) I decided on having the handle come back into the cockpit. Which lines up with it touching the top life line, which intersects near that spot. Leaving the lifeline between the handle and backstay adjuster being no trouble at all.

The throw on the new adjuster is longer than the original, not so much that it is useful .. but the tolerance now to get the backstay length exactly right has been increased a couple inches.

I NOW HAVE A SPARE ORIGINAL BACKSTAY. During this replacement I discovered (through lashing my original backstay adjuster, thereby shortening the backstay length) that the backstay adjuster isn't defective, just that my backstay was a bit too long and when I got near it's minimum length it was designed to intentionally let air in so the user can't damage it, and it can be reset by releasing it.

Not a necessary step, but it helped me make a decision on how much to shorten the backstay by installing the new harken first by lashing it to the stern (Kerry's idea), use it a couple of weeks, then measure to decide how much shorten backstay. Thinking I had a defective backstay this also allowed me to put the new backstay in service quickly, until what turned out a month until someone was available to shorten the backstay.

Cheers
Dan
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30101
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Location: Long Island Sound

Re: Harken Backstay Adjuster

Post by 30101 »

The seals on my Sailtec unit failed at the end of last season. The yard is recommending moving to the Harken unit in lieu of rebuilding the Sailtec unit.
I read the posts and was wondering if there was any further conversation about how the Harken unit has performed or any other issues with installation and use?
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Vento Solare
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Location: Newport, RI

Re: Harken Backstay Adjuster

Post by Vento Solare »

You can replace the seals if you have some mechanical ability, or a hydraulic shop can do it. Way less expensive than a replacement unit.

There are two Sailtec documents to help with the rebuild posted on the Drawings & Manuals page at this link: https://j109.org/info/drawings-manuals/
Dan Corcoran
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Re: Harken Backstay Adjuster

Post by Dan Corcoran »

I would recommend following Bill's advice to change the seals.

In favor of the Harken unit:
* Has a gauge, but its too hard to read in a bouncing sailboat. I still use a stick with lines as I did before, and never reference the gauge.

Against:
* I don't know why, but more prone to knuckle bruising. With practice in holding the handle towards the end of your fingers this is avoided, instead banging the soft part of your fingers.
Phoenix251
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Re: Harken Backstay Adjuster

Post by Phoenix251 »

Five years ago I sent original to sailtec for a rebuild. Has been rock solid since.
Dan Corcoran
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Re: Harken Backstay Adjuster

Post by Dan Corcoran »

Additional Cons:
Labor costs: Replacing the Harken also involves shortening the rod on the bottom and getting it correct within say 1/2 inch. Too short, and you will always have pressure on your backstay; too long, and you will lose the ability to achieve full tension.

While I could have calculated the length, i didn't want to screw up, so I first used AmSteel line (not legal) until I got the length where I wanted it. I wanted some slack to get the mainsail through on a light wind day, and some assurance that a small change in forestay length wasn't going to be a problem.
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